Influence of prefermentation clarification on the higher alcohol contents of wines

Nitrogenous compounds and the amount of solids have an effect on both the metabolic pathway and on the concentration of higher alcohols (HA) in wines. In this study, the influence of two prefermentation clarification treatments (static sedimentation and vacuum filtration) on the concentration of nitrogen which can be assimilated and glucose consumption have been studied with respect to HA concentration of wines. The results show that total HA decreased with increasing must clarification level, and the clarification is more of a determining factor than amino nitrogen. No relation has been found in these complex mediums between Leu concentration and the formation of isoamyl alcohol nor between Val and isobutyl alcohol. The concentration of n-propyl alcohol was unrelated to concentration and consumption of Thr and Gaba. There seems to be a relationship between slower glucose consumption in filtered musts and lower HA concentration in wines.